This invention relates to fuel production, including bio-diesel fuel production from vegetable oils and animal fats.
An oil source of alcoholysis of vegetable oils and animal fats can be used to produce fatty acid alkyl esters, which can be used as diesel fuels, generally referred to herein as “bio-diesel” fuels. In one production approach, non-enzymatic catalysts, such as alkali hydroxides and alcoholates, are used to facilitate the alcoholysis. A by-product of the alcoholysis is glycerol. The non-enzymatic catalysts are removed with the glycerol, and cannot be reused. Purification of glycerol is made difficult because it contains a large amount of the catalyst. In another production approach, enzymatic catalysts, such as lipases, are used to facilitate production of alkyl esters from natural oils in an alcoholysis reaction. An oil source having triglyceride and an alcohol are dissolved in an organic solvent. With a lipase as a catalyst, the triglyceride and the alcohol react to produce alkyl ester, with glycerol as by-product.